A letter by Atiq Ahmad with instructions to send it to the Uttar Pradesh chief minister and the chief justice of India in case of his death is being dispatched to them, the slain gangster-turned-politician's lawyer said on Tuesday.

"That letter in a sealed envelope is neither with me nor sent by me. It is kept somewhere else and being sent by some other person. I don't know the contents of the letter," said his lawyer Vijay Mishra.

Atiq Ahmad (60) and his brother Ashraf were shot dead at point-blank range by three men posing as journalists in the middle of a media interaction on Saturday night while police personnel were escorting them to a medical college in Prayagraj for a checkup.

"Atiq Ahmad had said that if there were any mishap or if he was murdered, the letter in the sealed envelope should be sent to the chief justice of India and Uttar Pradesh chief minister," Mishra told PTI.

The brothers, both jailed in Prayagraj, were in handcuffs when they were killed in full view of camera crews. The horrifying visuals were circulated widely on social media platforms and television channels. The last rites of Ahmad's son Asad, who was gunned down in a police encounter in Jhansi on April 13, were performed here just hours before the shooting.

They were brought to Prayagraj from Gujarat and Bareilly prisons for interrogation in connection with the killing of Umesh Pal and his two police security guards earlier this year.

Ahmad had moved the Supreme Court for protection, claiming that he and his family have been falsely implicated in the Umesh Pal murder case and he might be killed in a fake encounter by the Uttar Pradesh Police.